Coolant supply device

ABSTRACT

In a coolant supply device that supplies a coolant for washing chips into a machine tool, an opening/closing valve that is opened or closed by the pressure of the coolant is provided in the course of a pipe line supplying the coolant ejected from a coolant ejection pump into the machine tool. Meanwhile, an ON/OFF control is performed so that the coolant ejection pump is turned off when a first time elapses after the coolant ejection pump is turned on and the coolant ejection pump is turned on when a second time elapses after the coolant ejection pump is turned off.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a coolant supply device that causes a coolant for washing chips accumulated inside a machine tool to flow into an external chip receiving portion.

2. Description of the Related Art

When a cutting process is performed on a cutting target by using a cutting tool, chips are essentially produced. In the case of the cutting process using a machine tool, chips are accumulated inside the machine tool in an area surrounded by a splash guard, and hence the chips need to be discharged to the outside of the machine tool. Here, it is not efficient to manually discharge the accumulated chips by an operator. In many production sites, a coolant device has been used which causes chips accumulated in a machine tool to flow to the outside of the machine tool by using a coolant used for a cutting process.

The coolant device washing the machine tool is equipped with an ejection pump supplying a coolant for washing the inside of the machine tool in addition to an ejection pump supplying a coolant for cutting a cutting object by a cutting tool. A pipe is connected to the ejection pump, a nozzle is attached to a front end of the pipe, and the coolant ejected from the nozzle is supplied into the machine tool so as to discharge chips to the outside of the machine tool. However, the chips may have various shapes, materials, and weights, and some chips may exist inside the machine tool. In order to discharge the chips remaining inside the machine tool, a countermeasure is contrived which increases the capacity of the ejection pump or increases the number of the ejection pumps.

Further, Japanese Patent Application Laid-Open No. 2005-271088 discloses a technique in which a reservoir tank is provided at a position higher than a bed, a washing coolant is temporarily stored in the reservoir tank, an electromagnetic valve is opened when the level of the reservoir tank rises to a predetermined level, and then the washing coolant is ejected at a time. However, in this technique, the number of the pumps and the reservoir tanks needs to be increased, and the capacity of the pump needs to be increased to store the coolant at a high position. As a result, a problem arises in that the cost of the device increases as a whole.

Meanwhile, Japanese Patent Application Laid-Open No. 2007-30109 discloses a technique in which electromagnetic valves are provided in a plurality of ejection routes, the opening/closing timings of the electromagnetic valves are set, and the electromagnetic valves are opened or closed at different timings, so that chips are efficiently discharged even by a pump having a small capacity without decreasing the ejection pressure. However, since this technique is mainly used to highly efficiently discharge chips by the pump having a small capacity, the electromagnetic valves need to be used. Also, the cost of the device increases as a whole.

SUMMARY OF THE INVENTION

Therefore, an object of the invention is to provide a coolant supply device capable of simplifying the device and improving a chip removal performance of removing chips inside a machine tool by strengthening or weakening a coolant ejection pressure using an opening/closing valve opened or closed by the pressure of a coolant.

According to a first aspect of the invention, there is provided a coolant supply device including: a coolant tank that stores the coolant; a coolant ejection pump that suctions the coolant from the coolant tank and ejects the coolant; a pipe line that leads the coolant ejected from the coolant ejection pump into the machine tool and discharges the coolant into the machine tool; an opening/closing valve that is provided in the course of the pipe line and is opened or closed by the pressure of the coolant; and a pump control unit that controls turning on/off of the coolant ejection pump based on time.

In the coolant supply device of this aspect, since a valve (a relief valve, a pressure adjustment valve, or the like) opened or closed by a predetermined pressure is used instead of an electromagnetic valve, the cost may be decreased and the valve opening/closing operation may be controlled by switching on or off the ejection pump. Accordingly, since the coolant to be ejected may be strengthened or weakened, the chips remaining inside the machine tool may be easily treated. Further, since the ON/OFF state of the ejection pump is controlled based on time, it is possible to set an optimal driving time obtained by an experiment.

The pump control unit may be configured to control turning on/off of the coolant ejection pump so that the coolant ejection pump is turned off when a first predetermined time elapses after the coolant ejection pump is turned on and the coolant ejection pump is turned on when a second predetermined time elapses after the coolant ejection pump is turned off.

The pipe line may include a plurality of pipe lines, and the coolant ejected from the coolant ejection pump may be led into the machine tool through a branching device that causes the coolant to flow into the plurality of pipe lines.

According to a second aspect of the invention, there is provided a coolant supply device including: a coolant tank that stores a coolant for washing chips; a coolant ejection pump that suctions the coolant from the coolant tank and ejects the coolant; a pipe line that leads the coolant ejected from the coolant ejection pump into a machine tool and discharges the coolant into the machine tool; an opening/closing valve that is provided in the course of the pipe line and is opened or closed by the pressure of the coolant; a pressure sensor that detects the pressure of the coolant between the coolant ejection pump and the opening/closing valve; and a pump control unit that controls the ON/OFF state of the coolant ejection pump based on the output of the pressure sensor.

In the coolant supply device of this aspect, since a valve (a relief valve, a pressure adjustment valve, or the like) opened or closed by a predetermined pressure is used instead of an electromagnetic valve, the cost may be decreased and the valve opening/closing operation may be controlled by switching on or off the ejection pump. Accordingly, since the coolant to be ejected may be strengthened or weakened, the chips remaining inside the machine tool may be easily treated. Further, since the ON/OFF state of the ejection pump is controlled by the pressure sensor, it is possible to more accurately control the ejection pressure and the ejection amount.

The pipe line may include a plurality of pipe lines, and the coolant ejected from the coolant ejection pump may be led into the machine tool through a branching device that causes the coolant to flow into the plurality of pipe lines.

According to the invention, it is possible to provide a coolant supply device capable of simplifying the device and improving a chip removal performance of removing chips inside a machine tool by strengthening or weakening a coolant ejection pressure using an opening/closing valve opened or closed by the pressure of a coolant.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-described object, the other object, and the feature of the invention will be proved from the description of embodiments below with reference to the accompanying drawings. In these drawings:

FIG. 1 is a view illustrating a first embodiment of a coolant supply device according to the invention;

FIG. 2 is a flowchart illustrating a control of switching the ON/OFF state of a coolant ejection pump performed by a controller of FIG. 1;

FIG. 3 is a view illustrating a second embodiment of the coolant supply device according to the invention; and

FIG. 4 is a flowchart illustrating a control of switching the ON/OFF state of a coolant ejection pump performed by a controller of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, a first embodiment of a coolant supply device according to the invention which performs a control of switching the ON/OFF state of a coolant ejection pump based on ‘time’ will be described with reference to FIGS. 1 and 2.

FIG. 1 is a view illustrating a coolant supply device and a chips washing pipe disposed inside a splash guard of a machine tool.

As shown in FIG. 1, a coolant which is stored in a coolant tank 1 is suctioned by a coolant ejection pump 2, is divided into a plurality of routes through a manifold 4 that divides a coolant passageway, and reaches an opening/closing valve 7 through a plurality of pipes 5. The opening/closing valve 7 is a valve which is opened when a predetermined pressure is applied to the valve and is not opened unless the predetermined pressure is applied thereto. For that reason, even when the coolant reaches the opening/closing valve 7 through the pipe 5, a certain degree of time is needed until the opening/closing valve 7 is opened. Since the opening/closing valve 7 is opened when the predetermined pressure is applied thereto as described above, the coolant is ejected into a machine tool body 6 through a nozzle 8.

Furthermore, a configuration may be employed in which the pipe 5 is directly connected to the coolant ejection pump 2 instead of the configuration in which the passageway is divided into a plurality of passageways using the manifold 4, depending on the size of a machine tool.

The coolant which is ejected into the machine tool body 6 is ejected at a pressure stronger than a normal pressure as long as the opening/closing valve 7 is opened. When the coolant is continuously ejected, the pressure of the coolant inside the pipe 5 gradually and continuously decreases. However, the opening/closing valve 7 is maintained in an open state until the pressure of the coolant decreases to a predetermined pressure value.

A controller 10 performs a control of switching the ON/OFF state of the coolant ejection pump 2 based on time (first and second predetermined times T1 and T2 to be described later) by the use of a timer function.

A control of switching the ON/OFF state of the coolant ejection pump 2 performed by the controller 10 of FIG. 1 based on ‘time’ will be described with reference to the flowchart of FIG. 2.

[step SA01] The coolant ejection pump is turned on.

[step SA02] It is determined whether or not the first predetermined time T1 elapses after the coolant ejection pump is turned on. When the first predetermined time T1 elapses (YES), the routine proceeds to step SA03. Meanwhile, when the first predetermined time T1 does not elapse yet (NO), the routine proceeds to step SA03 after the first predetermined time T1 elapses.

[step SA03] The coolant ejection pump is turned off.

[step SA04] It is determined whether or not the second predetermined time T2 elapses after the coolant ejection pump is turned off. When the second predetermined time T2 elapses (YES), the routine proceeds to step SA05. Meanwhile, when the second predetermined time T2 does not elapse (NO), the routine proceeds to step SA05 after the second predetermined time T2 elapses.

[step SA05] It is determined whether or not the control of switching the ON/OFF state of the coolant ejection pump is still continued. When the control is continued (YES), the routine returns to step SA01 to switch on the coolant ejection pump again. However, when the control is not continued and the control of switching the ON/OFF state of the coolant ejection pump ends (NO), the process ends.

The flowchart will be additionally described.

When the coolant ejection pump 2 is turned on (step SA01), the coolant flows through the pipe 5 toward the opening/closing valve 7, and hence a predetermined pressure is applied to the opening/closing valve 7. For that reason, since the opening/closing valve 7 is opened, the coolant is sprayed from the nozzle 8 through the opening/closing valve 7, and is ejected into the machine tool body 6.

Then, when the coolant ejection pump 2 is turned off after the first predetermined time T1 elapses from the ON state of the coolant ejection pump 2 (step SA03), the coolant which flows through the pipe 5 toward the opening/closing valve 7 disappears, and hence the pressure applied to the coolant becomes zero. As a result, the opening/closing valve 7 is automatically closed.

The first predetermined time T1 and the second predetermined time T2 may be obtained by an experience through an experiment. The length of the first predetermined time T1 is not particularly limited. Specifically, there is a case where the pressure of the coolant flowing through the pipe 5 does not increase to a pressure enough for opening the opening/closing valve 7 until the coolant ejection pump 2 is turned off after the time T1 elapses even when the coolant is supplied to the pipe 5 by switching on the coolant ejection pump 2. In this case, when the coolant is supplied to the pipe 5 by switching on the coolant ejection pump 2 at the next time (after the time T2 elapses from the OFF state of the coolant ejection pump 2) without opening the opening/closing valve 7, the pressure of the coolant flowing through the pipe 5 increases to a pressure enough for opening the opening/closing valve 7 until the time T1 elapses therefrom (until the coolant ejection pump 2 is turned off).

Further, when the second predetermined time T2 is set to be short, the coolant ejection pump 2 is turned on before the pressure of the coolant inside the pipe 5 decreases to be an enough pressure, and hence the strength of ejection pressure of the coolant is weak.

The determination on whether to continue the control of switching the ON/OFF state of the coolant ejection pump in step SA05 is performed by a configuration in which the controller 10 monitors a state whether or not an operator presses a button (not shown) provided in the controller 10 or a configuration in which a chips washing time is set in advance by the controller 10 and the controller 10 monitors a state whether the set time elapses or not.

Next, a second embodiment of the coolant supply device of the invention performing the control of switching the ON/OFF state of the coolant ejection pump based on the ‘pressure of the coolant inside the pipe’ will be described with reference to FIGS. 3 and 4.

FIG. 3 is a view illustrating the coolant supply device and the chips washing pipe disposed inside the splash guard of the machine tool.

As shown in FIG. 3, the pressure sensor 3 is provided between the coolant ejection pump 2 and the opening/closing valve 7, and detects the pressure of the coolant ejected from the coolant ejection pump 2. As the pressure sensor 3, a sensor may be used which generates a signal when detecting a predetermined pressure. Meanwhile, the opening/closing valve 7 is a valve which is opened when a predetermined pressure is applied thereto and is not opened until the predetermined pressure is applied thereto similarly to the opening/closing valve 7 shown in FIG. 1. As a result, when the opening/closing valve 7 is opened so that the pressure of the coolant ejected from the coolant ejection pump 2 toward the pipe 5 increases to the predetermined pressure, a signal is output from the pressure sensor 3.

When the controller 10 receives a detection signal PA from the pressure sensor 3, the coolant ejection pump 2 is turned off. When the coolant ejection pump 2 is turned off so that the coolant is not ejected and the pressure of the coolant decreases to a predetermined value, the signal PA output from the pressure sensor is stopped and the coolant ejection pump 2 is turned on.

In this way, when the control of turning on/off of the coolant ejection pump 2 shown in FIG. 4 is repeated, the coolant to be ejected may be strengthened or weakened, and hence the chips remaining inside the machine tool body 6 may be easily discharged to the outside of the machine tool.

Furthermore, a sensor which simply detects the pressure of the coolant inside the pipe 5 may be used as the pressure sensor 3. In this case, a pressure detection signal (a measurement value) output from the pressure sensor 3 is compared with a reference pressure set in advance inside the controller 10, and an output signal is output when the measured coolant pressure is larger than the reference pressure.

The control of switching the ON/OFF state of the coolant ejection pump 2 performed by the controller 10 of FIG. 3 based on the ‘pressure of the coolant inside the pipe’ will be described with reference to the flowchart of FIG. 4.

[step SB01] The coolant ejection pump is turned on.

[step SB02] It is determined whether the detection signal PA from the pressure sensor is in an ON state or not. When the detection signal PA is in an ON state (YES), the routine proceeds to step SB03. Meanwhile, when the detection signal PA is not in an ON state (NO), the routine proceeds to step SB03 after the detection signal PA turns into an ON state.

[step SB03] The coolant ejection pump is turned off.

[step SB04] It is determined whether the detection signal PA from the pressure sensor is in an OFF state. When the detection signal PA is in an OFF state (YES), the routine proceeds to step SB05. Meanwhile, when the detection signal is not in an OFF state (NO), the routine proceeds to step SB05 after the detection signal PA turns into an OFF state.

[step SB05] It is determined whether switching control of turning on/off of the coolant ejection pump is still to be continued or not. When the switching control is to be continued (YES), the routine returns to step SB01 so as to switch on the coolant ejection pump again. When switching control of turning on/off of the coolant ejection pump is to be stopped (NO), without continuing the switching control, on the other hand, the process ends.

As described above, the coolant supply device according to the invention is mainly used to highly efficiently discharge the chips even in a pump having a small capacity. When the opening/closing valve 7 (a relief valve, a pressure adjustment valve, or the like) configured to be opened or closed by the pressure of the coolant is used, a decrease in cost may be realized and the ejection pressure may be strengthened or weakened. Further, if the opening/closing valve 7 is configured to be opened when the pressure of the coolant increases to a predetermined value, the opening/closing valve 7 is opened or closed only by the pressure of the fluid. For this reason, the opening/closing operation may be indirectly controlled by carrying out switching control of turning on/off of the ejection pump. 

1. A coolant supply device that supplies a coolant for washing chips into a machine tool, the coolant supply device comprising: a coolant tank that stores the coolant; a coolant ejection pump that suctions the coolant from the coolant tank and ejects the coolant; a pipe line that leads the coolant ejected from the coolant ejection pump into the machine tool and discharges the coolant into the machine tool; an opening/closing valve that is provided in the course of the pipe line and is opened or closed by the pressure of the coolant; and a pump control unit that controls turning on/off of the coolant ejection pump based on time.
 2. The coolant supply device according to claim 1, wherein the pump control unit is configured to control turning on/off of the coolant ejection pump so that the coolant ejection pump is turned off when a first predetermined time elapses after the coolant ejection pump is turned on and the coolant ejection pump is turned on when a second predetermined time elapses after the coolant ejection pump is turned off.
 3. The coolant supply device according to claim 1, wherein the pipe line includes a plurality of pipe lines, and the coolant ejected from the coolant ejection pump is led into the machine tool through a branching device that causes the coolant to flow into the plurality of pipe lines.
 4. A coolant supply device that supplies a coolant for washing chips into a machine tool, the coolant supply device comprising: a coolant tank that stores the coolant; a coolant ejection pump that suctions the coolant from the coolant tank and ejects the coolant; a pipe line that leads the coolant ejected from the coolant ejection pump into the machine tool and discharges the coolant into the machine tool; an opening/closing valve that is provided in the course of the pipe line and is opened or closed by the pressure of the coolant; a pressure sensor that detects the pressure of the coolant between the coolant ejection pump and the opening/closing valve; and a pump control unit that controls the ON/OF state of the coolant ejection pump based on an output of the pressure sensor.
 5. The coolant supply device according to claim 4, wherein the pipe line includes a plurality of pipe lines, and the coolant ejected from the coolant ejection pump is led into the machine tool through a branching device that causes the coolant to flow into the plurality of pipe lines. 